Background Comorbidities associated with systemic inflammation including cardiovascular disease (CVD), stroke and diabetes mellitus (DM) are common among individuals with chronic obstructive pulmonary disease (COPD). A study was undertaken to quantify the burden of comorbidity and to determine the risk of first acute arteriovascular events among individuals with COPD. Methods The computerised primary care records of 1 204 100 members of the general population aged $35 years on 25 February 2005 were searched for recordings of each disease. Data were analysed using multivariate logistic regression. Cox regression was used to determine whether individuals with COPD were at increased risk of acute myocardial infarction (MI) and stroke. Results Cross-sectional analyses showed that physiciandiagnosed COPD was associated with increased risks of CVD (OR 4.98, 95% CI 4.85 to 5.81; p<0.001), stroke (OR 3.34, 95% CI 3.21 to 3.48; p<0.001) and DM (OR 2.04, 95% CI 1.97 to 2.12; p<0.001). In the follow-up analyses, after adjusting for confounding by sex and smoking status and stratifying for age, the greatest increase in the rate of acute arteriovascular events was found in the youngest age groups; the HR for acute MI was 10.34 (95% CI 3.28 to 32.60; p<0.001) and for stroke the HR was 3.44 (95% CI 0.85 to 13.84; p<0.001) compared with the oldest age group. Conclusion Individuals with COPD are substantially more likely to have pre-existing CVD, DM or a previous stroke and are at high risk of acute arteriovascular events. National COPD guidelines and models of care need to adapt to provide an integrated approach to addressing these comorbidities.
BackgroundEpidemiological studies suggest that hookworm infection protects against asthma, and therefore that hookworm infection may have a direct or an indirect therapeutic potential in this disease. We now report the first clinical trial of experimental hookworm infection in people with allergic asthma.ObjectivesTo determine the effects of experimental hookworm infection in asthma.MethodsThirty-two individuals with asthma and measurable airway responsiveness to adenosine monophosphate (AMP) were randomized and double blinded to cutaneous administration of either ten Necator americanus larvae, or histamine solution (placebo), and followed for 16 weeks. The primary outcome was the change in provocation dose of inhaled AMP required to reduce forced expiratory volume in 1 s by 20% (PD20AMP) from baseline to week 16. Secondary outcomes included change in several measures of asthma control and allergen skin sensitivity and the occurrence of adverse effects.ResultsMean PD20AMP improved in both groups, more in the hookworm [1.49 doubling doses (DD)] than the placebo group (0.98 DD), but the difference between groups was not significant (0.51 DD; 95% confidence interval: −1.79 to 2.80; P=0.65). There were no significant differences between the two groups for other measures of asthma control or allergen skin sensitization. Infection was generally well tolerated.ConclusionsExperimental infection with ten hookworm larvae in asthma did not result in significant improvement in bronchial responsiveness or other measures of asthma control in this study. However, infection was well tolerated and resulted in a non-significant improvement in airway responsiveness, indicating that further studies that mimic more closely natural infection are feasible and should be undertaken.Cite this as: J. R. Feary, A. J. Venn, K. Mortimer, A. P Brown, D. Hooi, F. H. Falcone, D. I. Pritchard and J. R. Britton, Clinical & Experimental Allergy, 2010 (40) 299– 306.
Intestinal parasite infection appears to protect against allergic sensitization. Work should continue to identify the mechanisms of this effect and means of harnessing these to reduce the global burden of allergic disease.
Epidemiological studies suggest that a hookworm infection producing 50 eggs/gram of feces may protect against asthma. We conducted a dose-ranging study to identify the dose of hookworm larvae necessary to achieve 50 eggs/gram of feces for therapeutic trials of asthma. Ten healthy subjects without asthma or airway hyperresponsiveness to inhaled methacholine received 10, 25, 50, or 100 Necator americanus larvae administered double blind to an area of skin on the arm. Subjects were seen weekly for 12 weeks and were then treated with mebendazole. Skin itching at the entry site and gastrointestinal symptoms were common at higher doses. Lung function did not change. Levels of blood eosinophils and IgE increased transiently, and levels of IgG increased progressively. All doses resulted in at least 50 eggs/gram of feces in the eight subjects who completed the study. Infection with 10 N. americanus larvae is well tolerated, elicits a modest host eosinophil response, and is potentially suitable for use in preliminary clinical therapeutic trials.
BackgroundEpidemiological evidence suggests that hookworm infection protects against asthma. However, for ethical and safety reasons, before testing this hypothesis in a clinical trial in asthma it is necessary to establish whether experimental hookworm infection might exacerbate airway responsiveness during larval lung migration.ObjectiveTo determine whether hookworm larval migration through the lungs increases airway responsiveness in allergic individuals with measurable airway responsiveness but not clinical asthma, and investigate the general tolerability of infection and effect on allergic symptoms.MethodsThirty individuals with allergic rhinoconjunctivitis and measurable airway responsiveness to adenosine monophosphate (AMP) but not clinically diagnosed asthma were randomized, double-blind to cutaneous administration of either 10 hookworm larvae or histamine placebo, and followed for 12 weeks. The primary outcome was the maximum fall from baseline in provocative dose of inhaled AMP required to reduce 1-s forced expiratory volume by 10% (PD10AMP) measured at any time over the 4 weeks after active or placebo infection. Secondary outcomes included peak flow variability in the 4 weeks after infection, rhinoconjunctivitis symptom severity and adverse effect diary scores over the 12-week study period, and change in allergen skin test responses between baseline and 12 weeks.ResultsMean maximum change in PD10AMP from baseline was slightly but not significantly greater in the hookworm than the placebo group (−1.67 and −1.16 doubling doses; mean difference −0.51, 95% confidence interval −1.80 to 0.78, P=0.42). Symptom scores of potential adverse effects were more commonly reported in the hookworm group, but infection was generally well tolerated. There were no significant differences in peak-flow variability, rhinoconjunctivitis symptoms or skin test responses between groups.ConclusionHookworm infection did not cause clinically significant exacerbation of airway responsiveness and was well tolerated. Suitably powered trials are now indicated to determine the clinical effectiveness of hookworm infection in allergic rhinoconjunctivitis and asthma.
Asthma is the most common respiratory disorder in the UK, yet we have incomplete knowledge on the prevalence of current disease, treatment and exacerbations.We used UK electronic healthcare records, 2006–2016, to estimate the prevalence of current asthma by year, sex and age (<5, 5–11, 12–17, 18–24, 25–54 and ≥55 years), and the proportion prescribed inhaled corticosteroids (ICS) and additional asthma therapy, treated for exacerbations and other asthma care markers.Overall current asthma prevalence was 6.5% in 2016 (7.2% in 2006). Prevalence fell in those aged <45 years. The lowest prevalence and largest absolute decrease was in children aged <5 years. In 2016, 80% of current asthma patients were managed on ICS (65% in 2006); this increase occurred in all age groups, primarily due to an increase in low-dose ICS. During this time there was an increase in all age groups in the proportion prescribed additional asthma therapy, treated for an exacerbation within primary care and given an annual asthma review or management plan. Hospitalised exacerbations showed minimal change over time.Asthma remains highly prevalent and a significant healthcare burden. In those with a diagnosis, there was an increase in ICS prescriptions and treatment of exacerbations across all age groups. This may reflect a trend towards more aggressive asthma management within primary care. An apparent decline in prevalence was observed in those aged <45 years, particularly in children aged <5 years.
Abstract. Data from epidemiologic studies suggest that hookworm infections, in establishing an immunologic phenotype conducive to parasite survival, may protect against the development of allergic disease. We describe immunologic findings from a clinical study designed to investigate the safety of iatrogenic hookworm infection in participants with allergic rhinitis. The low, relatively safe level of hookworm infection used in this study was immunogenic, inducing eosinophilia and a significant specific IgG response. Importantly, no potentiation of IgE responses to the environmental allergens to which the participants were sensitized was seen. However, no evidence of systemic immune regulation was seen in infected participants. This finding may indicate that the level of infection or the frequency of infection may have to be altered in future trials to induce a therapeutically conducive immunologic phenotype.
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